SUPER-SUMMED-AND-DIFFERENTIAL HARMONIC OSCILLATIONS OF AN UNSYMMETRICAL SHAFT AND AN UNSYMMETRICAL ROTOR

Super-summed-and-differential harmonic oscillations in rotating shaft systems are studied theoretically and experimentally. This kind of nonlinear forced oscillation occurred experimentally in the unsymmetrical shaft system carrying a disc and in the unsymmetrical rotor system where the rotor was mounted on a shaft with circular cross section (a round shaft). We have also compared these oscillations with those in the system where a disc is installed on a round shaft. It is concluded theoretically that large unsymmetry of a rotating shaft or a rotor makes it easier for super-summed-and-differential harmonic oscillations to occur in a rotating shaft system. Not only stable stationary oscillations but also unstable ones may occur. The experimental results are consistent qualitatively with those theoretical ones.